A light-emitting diode includes a first type semiconductor layer, a stress relief layer disposed on the first type semiconductor layer and including at least one first repeating unit containing a first well layer and a first barrier layer that are alternately stacked, an active layer disposed on the stress relief layer and including at least one second repeating unit containing a second well layer and a second barrier layer that are alternately stacked, a second type semiconductor layer disposed on the active layer, a first electrode electrically connected to the first type semiconductor layer, and a second electrode electrically connected to the second type semiconductor layer. The first well layer is made of an In-containing material. The second well layer is made of an In-containing material. The second barrier layer is formed with multiple sub-layers, each of which is made of an Al-containing material.